Pig Manure Composting Technology

Pig manure, the superior organic fertilizer, contains great numbers of nitrogen, phosphorus and potassium that are essential for plant growth, increasing production of food crops. In general, the ingredients of pig manure are 63.7g/kg crude organics, 2.1g/kg total nitrogen, 0.9g/kg total phosphorus, 1.1g/kg total potassium, 1.8g/kg calcium, 0.7g/kg magnesium, 0.3g/kg sulfur, 37.6mg/kg copper, 137.2mg/kg zinc, 6.0mg/kg iron, 425.5mg/kg manganese, 9.2mg/kg boron and 1.0mg/kg molybdenum, etc. Only through full decomposition can pig manure be applied to soil. If not, it’s easy to burn the root system, and the injurious insect incubated by worm eggs from pig manure will add the harm to crops. After fully decomposed, pig manure can become high quality manure mixture for fertilizing, which can be used as high grade base fertilizer for plant crops or as commercial organic fertilizer to sale after subsequent process.

Fermentation of Pig Manure1. Static Pile:
This fermentation method takes longer time but spends lower cost. To be specific, blend the pig manure and soil uniformly under the environment of over 15 degree, and cover the dunghill with plastic cloth, which can accelerate the fermentation speed. The fermentation will be finished if there are steam and white filaments with certain temperature when opening the cloth on dunghill after long-time natural decomposition. Then farmers can transport the pig manure to farmland as base fertilizer. By the way, there is no need for this fermentation method to draw support from composting machines, and it’s only suitable for families with low-cost composting production.

Weakness of static pile:
-Decomposition time is long(always taking 4-6 months), or longer if under low temperature, and composting fermentation effect is bad.
-Occupying the site and polluting surroundings because of long-term stacking.
-Dungs through natural composting fermentation are rotten and wet, hard to transfer and apply directly.
-Natural composting fermentation cannot very well eliminate pathogenic bacteria, worm eggs and other hazardous substance, which can easily cause bacterial infection for plants.

2. Commercial pig manure windrow composting:
The fermentation of commercial windrow composting must draw support from compost turner, which can not only ensure the quality of material pile-turning, but also save whole fermentation time and improve working efficiency. In composting facilities, the most common pile-turning machine is Full Hydraulic Crawler Type Compost Turner.

Material proportion. Blend the pig manure with straw, saw dust and mushroom residue according to appropriate proportion(manure accounts for 80%-90% while others accounts for 10%-20%). The proportion is 1t materials (about 2.5t fresh materials) plus 1kg leavening agents, throwing 1kg leavening agents plus 5kg rice bran (or bran, corn flour and other substitution) into materials stack after attenuation, and then mixed fermenting. That is, before mixing, strains need 5 times attenuation with some thinner materials like bran powder or corn flour, beneficial to uniform blending, after the uniform blending of strains and diluting agent, adding them into pig manure and other materials to blend uniformly again. It’s better to add straw or mushroom residue to adjust C:N ratio, which can also avoid nonuniform nutrient caused by single material. The common carbon rich materials refer to saw powder, sawdust, manioc waste, bagasse, straw powder, peanut hull powder, rice hull powder, cirrus crushed material and so on. See more at: Compostable Materials Around us.

Building material compost piles. It’s not good to build too small and too low pile because too small pile will make a bad effect on fermentation. The fermentation effect will be better with pile of 1.5m – 2m height, 2m width and 10m-20m length or bigger one, which is also convenient for compost turner to work. But compost turners with different models have different requirements for material pile’s height and width. Hydraulic Auxiliary Crawler Window Compost Turner for example:

Model

XGFD-2300

XGFD-2600

XGFD-3000

Width of the pile

2300mm

2600mm

3000mm

Height of the pile

600mm-1000mm

1000-1300mm

1300mm-1500mm

Temperature requirement. Starting temperature should be at least 15 Degree Celsius (available to work at all seasons, free of season effect, trying to make fermentation indoor or within greenhouse in winter). During fermentation process, appropriate oxygen supply and turning should be noted, and temperature must be controlled within 55-65 Degree Celsius because too high temperature will affect the nutrient. When using livestock and poultry manure as raw material, ammonia gas will neutralize some organic acid generated by material decomposition, so it needs to add 5% ground phosphate rock that is very effective to adjust the PH value of materials.

Compost Pile Temperature Reflects the Stage of Compost:

In aerobic composting proper temperature is important. Temperature is a key index for compost. Does system heat up or not? How long does it keep? How do mixtures affect temperature? All of these are concerned by composting workers.

Heat is generated by degradation of organism, so workers can judge the stage of compost and how the decomposition course is going, according to compost temperature. For instance, if compost temperature is up to 40 or 50 Degree Celsius, it can be concluded that compost contains enough nitrogen and water content to support microorganism growing rapidly.

When monitoring compost temperature, please make sure the thermometer goes deep into compost for a while, read it after temperature getting steady, then move it to another new place (including the temperatures at different depth places from top edge). Sometimes the temperature of compost is high while sometimes is low, mainly depending on water content and chemical component of compost. Generally, compost temperature change has certain gradient change rule, for the system with ventilation at the bottom, the position with highest temperature is about at the place 2/3 away from bottom or higher place.

Making the graph based on the compost temperature changing with time, then people can judge the situation of decomposition process. A good compost system will reach 40 or 50 Degree Celsius within two or three days. After the resoluble organic substance are exhausted, temperature will start to descend, and decomposition course will become slow relatively.

All temperatures mainly depend on how much heat microorganism generates, and how much heat loss due to ventilation and surface cooling. While how long system keeping warm depends on chemical constituent of compost, and system size and shape. Besides, water content can also affect temperature change because water specific heat is higher than others’, so if with enough water content for microorganism growth, the temperature rising and lowering of drier mixture will be faster than that of wetter mixture.

Water content requirement. The water content of fermentation materials should be controlled at around 65%. Too high or too low are both adverse to fermentation because too little water will slow down the fermentation speed while too much water will lead to bad ventilation and slow heating with foul smell. The ways to adjust materials water content show as follows: add straw, saw dust and mushroom residue into pile when too much water. How to judge water content is appropriate: griping the handful materials, water stain can be seen but without dropping and the materials disperse once falling to the ground.

Turning piles for ventilation. During fermentation process, pay attention to oxygen supply and piles turning, starting to turn when temperature up to 60 Degree Celsius and doing this once a day, but if temperature is over 65 Degree Celsius, it needs multiple piles turning. Remember, control the temperature at 65 Degree Celsius because too high temperature will have a bad effect on nutrient.

Finishing fermentation. With the help of compost turner, chicken manure compost piles always take about 5 -7 days to finish the deodorization, fermentation compost and sterilization, etc. The sign of compost: normal pile temperature, black brown and loose materials, no original foul smell, a little ammonia odour and white hypha. The finished chicken manure organic fertilizers are fluffy with a little winey or earthy taste and rich nutrition, which is more convenient to apply in farmland and higher value when applied to fruit and vegetables, commercial crops, flowers and plants. If adding too much saw dust, rice hull and other auxiliary materials, the fermentation time should be prolonged for sufficient compost.

Pig manure mixture for fertilizing is effective method to process manure with resource, reduction and harmlessness, and maturity is the important criterion for organic fertilizer plant to design, run, control composting process and assess composting products quality.